1. Field of the Invention
The present invention relates generally to pressure transducers and more particularly to a pressure transducer which utilizes a semiconductor diaphragm and is substantially miniaturized in size and of the super-thin, high sensitivity type.
2. Description of the Prior Art
When there is a need to accurately measure local pressures acting upon fluid-contacting surfaces, such as for example, the surface of an aircraft or the surface of a turbine blade, it is of supreme importance to use a pressure transducer which is highly responsive to such pressure and can accurately detect minor pressure changes. For this purpose, there has been widely used a semiconductor diaphragm type pressure transducer which can detect the pressure by utilizing the principle that the resistivity of semiconductor elements formed upon a diaphragm varies in accordance with the strain exerted upon the semiconductor elements by means of the pressure applied to the diaphragm according to a so-called peizoresistive effect. This semiconductor diaphragm type pressure transducer has a greater degree of sensitivity and is more compact in size as compared with conventional pressure transducers within which a semiconductor diaphragm is not employed.
However, such a semiconductor diaphragm type pressure transducer has disadvantages in that, when mounted upon the local portion of the aircraft wing surface or upon the surface of a turbine blade which is in contact with a fluid, the profile drag of the pressure transducer disturbs the flow of the fluid, and in this connection, the pressure transducer incorporating semiconductor elements having a high degree of sensitivity is insufficient in overcoming the aforesaid disadvantages, and thus it is required to provide a pressure transducer which is substantially miniscule in size in order to produce a negligible amount of disturbance. More particularly, when the pressure transducer is mounted upon the aircraft wing surface, it is possible to minimize the drag of the pressure transducer in the direction extending along the wing surface by smoothing the surface of the device which is parallel with the wing surface, however it is extremely difficult to minimize the height or thickness of the pressure transducer in the direction perpendicular to the wing surface.